1. Field of the Invention
The present invention generally relates to an optical waveguide bio-sensing device and, more particularly, to an optical waveguide bio-sensing device using a grating chip with a sub-wavelength grating to serve as a platform for molecular interaction so as to detect bio-molecular interactions, reaction rate and/or molecular dynamics without any labeling in real time. Optical systems using the present invention are simplified and capable of being portable. Thus a high sensitivity detection technique is achieved.
2. Description of the Prior Art
Bio-technology is regarded as the most important field of research and the most potential industry that most countries have put emphasis upon. Bio-technology includes agricultural bio-technology, bio-pharmaceutical technology and genomic and therefore it is crucial in pharmaceutics, genomics and proteomics.
In bio-molecular interaction analysis (BIA), bio-chips have attracted tremendous attention from genomics into proteomics. Bio-chips are used to detect genetic performance and bio-molecular messages. The current detection is done mainly by fluorescence detection. In fluorescence detection, problems related to complicated fluorescence tags, difficulty in molecule tags, inevitable fluorescence decay and unavailability in dynamics information of real-time interaction occur. Therefore, a label-free detecting method is required. In 1902, R. W. Wood discovered exceptional reflection gratings. Afterwards, theoretical reports and experiments on various grating structures such as guided-mode resonant sub-wavelength gratings were found in literature.
In U.S. Pat. No. 6,483,096 entitled “Integrated-optical chemical and biochemical sensor”, it is disclosed a biochemical sensing technology for molecular detection by using the tunable laser diode and the phase-locked loop (PLL) technique. However, the tunable laser diode provides a narrower range of wavelength and thus a high-precision goniometer is required so as to couple the incident light into the waveguide at a correct angle for resonance coupling.
Furthermore, in U.S. Patent Application Doc. No. 20030068657 entitled “Label-free methods for performing assays using a colorimetric resonant reflectance optical biosensor”, it is disclosed a label-free methods for performing assays using a calorimetric resonant reflectance optical biosensor. In this method, a grating is provided on a molecular detection platform for molecular implantation. Monochromatic light appears after light passes the grating. A sample to be tested is disposed on the platform and is then illuminated by a white light beam. The wavelength of the incident light is changed after reflection because the molecules of the tested sample are bound to react with receptors on the grating. The change in wavelength can be detected by a spectrum analyzer so as to measure the thickness of the protein without using a probe for detecting fluorescence as well as radioactive tags. However, the reflectance spectrum exhibits a wide FWHM (full width at half magnitude) leading to a poor wavelength resolution so that detection in physiology concentration is unavailable.
Therefore, to overcome the aforementioned shortcomings, there is need in providing an optical waveguide bio-sensing device so as to detect bio-molecular interactions, reaction rate and/or molecular dynamics without any labeling in real time.